John w



UNITED STATES PATENT OFFICE..

W. CLOUD, OF ALTOONA, PENNSYLVANIA, ASSIGNOR 0F ONE-THIRD TOQHARLES F.HOUGHTON, OF CORN ING, NEW YORK.

Lesse.-

SLECIFICA TION forming part of Letters Patent No. 32.5.'656, datedSeptember 8, 1.8875.l Application man July s, 18st. (noni-1.)

To alt whom it ntcy concern.-

Be it know'n that I, JOHN W, Omni), 'of Altoona, in the county of Blairand State of Pennsylvania, have invented cert-ain new and My inventionrelates to lenses adapted to service on' railways, or for any purposewhere are reqnr'd','where itis desirable to cast. the rays of light in awidened form in a horizontal di reetion; and the novelty consists in theconstruction, form, arrangement, and adaptation of parts, as will behereina fter more fully set l'orth, and particularly pointed outin theclaims.

.The object of myv invention is. to produce a lens vot'vsnch'shape thatwhen a source of light is placed behind it the beam of light will bewidened ont'into a band whose cross-section will begreater in onedirectionthan in the direction at right angles thereto. I form the lensof two curved surfaces, the `inner being concave and a section of thesurface of a sphere, and theoute'r being convex and a section ofthesurface of a flattened spheroid.

The invention is illustrated in the accompanying drawings, which forni apart of this specification, and'in which- Fignrel represents a frontview showing the outline of the convex surface in fll line and of theconcave in dotted line. Fig.. 2 is a secti n'taken on the line AB ofFig. 1. Fig. 3 is section taken on the line C D of the same figure, andFig. 4 represents the cross section of the beam of light produced.`

Upon the section A B the surfaces are apcome nearly parallel on leavingthe lens, as

seen in Fig. 3. i

The combination of the spherical concave and spheroidal convex surfaceswill cause the refracting substance to be of uniform thickness. in thecross-section A B, but of varying thickness, being thicker at the centerin the cross- 55 section C D, the first not causing refraction, but

the second causing the rays to be refracted toward each other, therebyproducing the result desired. The beam of light so produced is of anelliptical crosssection, and is represented 6o by Fig. 4. The innersuifaccniay beperfectly flat and same cii'ect-produccd.

Having described my invention, what l.

claim, and desire to secure by Letters Patent,

1. A lens having a concave sphercilsurface and a convex spheroidalsurface, arranged and adapted to serve substantially as shown anddescribed, and for the purposes set forth.

2.- A lens having a concave surface in form V7o of a section of asphere, and a convex spheroidal surface, whereby two cross-sections ofthe lens at right angles are made different from cach other, in one thethickness being uniform and in the other being thickest at the 75center, thereby causing thebeain of light,after passing through thelens, to be of elliptical crosssection, as set forth.

In testimony that I claim the foregoing as my own I havehcreto allixedmy signature in 8o presence of two witnesses.

JNO. YV. CLOUD.A

Witnesses:

SAMUEL Poncnnn, Pant. KREUzroTNTNEn.

